1. Field of the Invention
The present invention relates to the field of viral purification, in particular to a method for obtaining viruses from a liquid viral suspension.
2. Summary of the Related Art
Methods for purifying viral suspensions are known in the pharmaceutical field, and in particular in the vaccines field.
Thus, patent FR2201079 describes, in particular, a method for purifying viruses from a viral suspension which is introduced into a zonal centrifuge rotor while it is stopped; after the rotor has begun to slowly rotate (between 2000 and 5000 rpm), at least 2 cushions of liquid of different density are introduced at the periphery of the rotor; then, once the rotor is filled with the liquid to be treated, said rotor is accelerated to a speed sufficient to separate the viruses from the impurities and, finally, after the speed of the rotor has been brought back to between 2000 and 5000 rpm, a liquid of density equal to or greater than the content of the rotor is introduced by the periphery, in order to empty the rotor by its central channel; and the fractions containing the virus freed of the impurities is subsequently collected.
During rotation, the cushions of different density are converted by diffusion into a nonlinear gradient.
The method described in said patent, which is a discontinuous method, has however the drawback of making it possible to process only constant and limited volumes of viral suspension, and therefore of making it necessary to pre-concentrate the viral suspension to be purified and/or to reproduce the same procedures several times in order to process a large volume of liquid.
The fact of using such a method also complicates attempts to have a process which is carried out entirely under sterile conditions.